The present invention relates to a method and an arrangement for feeding a two-way pallet onto a roller path in which the two-way pallet is fed by means of forklift devices onto the roller path, transported by the roller path, and removed from the roller path by means of forklift devices.
The transportation of stackable goods is effected to a large extent on pallets. The pallets most frequently used are American or Australian standard pallets which are used primarily in the United States of America, Australia and the Far East. On the Continent, on the other hand, European pool pallets, so-called Euro pallets are used. Said pallets have a rectangular or square base surface. The essential difference between the U.S./Australian pallets and Euro pallets is that the Euro pallets, deposited on a continuous surface such as, for instance, the loading surface of a truck or the floor of a warehouse, can be gripped on all four sides by the forks of a forklift device and lifted for transportation. For this reason, the Euro pallet is also known as a four-way pallet. The U.S./Australian pallet, on the other hand, can be gripped and lifted for transportation by the forks of a forklift device only from two opposite directions, for which reason it is also known as a two-way pallet. This is based on the different construction of said pallets.
The U.S./Australian pallets, as well as the Euro pallet, consist of wood.
A Euro pallet, viewed from its standing surface up to the loading surface, is developed in the manner that the lowermost layer, serving as standing surface, consists of three elongated bottom boards arranged spaced apart and parallel to each other. Three blocks which are arranged on these bottom boards, spaced apart in the longitudinal direction of the boards. The first as well as the last block terminate flush with the beginning and end respectively of the individual bottom boards, while the remaining block is arranged in the center. The width of the boards and the width of the individual blocks are the same. On the top of the blocks, elongated intermediate boards are again arranged parallel to and spaced from each other, they extending over the corresponding blocks and their starting and stopping ends terminating flush with the outer blocks. The longitudinal axes of the intermediate boards extend perpendicular to the longitudinal axes in the same direction as the bottom boards. As a general rule, the Euro pallets are gripped by a forklift device in the manner that the forks of the forklift device extend in the direction of the longitudinal axes of the bottom and top boards. The forks of the forklift device then engage for the transporting away of the Euro pallet into the spaces left by the blocks and bottom boards. If necessary, the Euro pallet, due to the space between the individual blocks, can, to be sure, also be gripped and transported away from a standing surface from the adjacent sides, i.e. 90.degree. away. The forks of the forklift device then engage into the spaces formed between the bottom boards, the blocks and the intermediate as well as top boards.
In the U.S./Australian pallet, elongated bottom boards, also arranged spaced from and parallel to each other, are present as standing surface. As compared with the Euro pallet, the space between the bottom boards is very much smaller, but it may also vary. Continuous scantlings are arranged on the bottom boards, extending perpendicular to the longitudinal axes. The scantlings extend parallel to each other and are spaced apart. As loading surface, elongated top boards extending parallel to and spaced from each other are placed on the top side of the continuous scantlings. The top boards have their longitudinal axes extending perpendicular to the longitudinal axes of the bottom boards. For removal by a forklift device, the forks are introduced into the space formed by the top boards, bottom boards and scantlings. The forks then necessarily point with their longitudinal axes in the direction of the longitudinal axes of the scantlings and thus perpendicular to the longitudinal axes of the bottom and top boards. Since the transporting away of the U.S./Australian pallet is thus possible only from two directions, the U.S./Australian pallet is also known as a two-way pallet.
Upon the transporting of two-way pallets on roller paths, for instance in a conveyor storage in which, as a general rule, several roller paths are arranged in a plane alongside of each other, the development of the two-way pallet is a definite disadvantage. Lateral charging of the pallets onto roller paths is generally not possible due to considerations of space as well as reasons of safety and due to the lateral limitation of the roller path. If a two-way pallet is placed onto the roller path in direction of conveyance, the longitudinal axes of the bottom boards necessarily extend perpendicular to the direction of travel of the roller path, i.e. in the direction of the longitudinal axis of the individual rollers of the roller path. The bottom boards of the two-way pallet accordingly have their longitudinal axes transverse to the direction of transport of the roller path. When using roller paths with continuous individual roller, i.e. rollers which extend over the entire width of the roller path, considerable difficulties result upon the transport due to the necessary alignment of the bottom boards parallel to said rollers. Even in the event that the bottom boards have still not warped or loosened in part or were from the start uneven or curved, the longitudinal axes of the bottom boards become caught in the spaces present between the individual rollers of the roller path and prevent or impede the further transport. Since, in the course of time, the bottom boards are subject to warping and loosening of the scantlings, the transport on the roller path is even more impeded. In this connection, it is not rare that individual two-way pallets can no longer be conveyed at all on the roller path or, even worse, remain stuck on the roller path during the course of the transport and block the further transport of the adjacent pallets.
This disadvantage, which has been known for a long time, has been overcome up to now by using for the transport of two-way pallets roller paths which, as seen over the width of the roller path, have individual rollers which are shorter than the roller path and are arranged with their gaps shifted, with respect to each other. In this way, there is prevented the formation, seen over the width of the roller path, of a continuous space between the rollers in which the bottom boards could become stuck. Such a construction of a roller path due to the plurality of rollers as compared with a roller path having rollers which are continuous over the entire width of the roller path, is however very much more expensive already in the expense for the individual rollers and the corresponding supporting elements than a roller path with continuous rollers. Furthermore, roller paths developed in this manner are considerably more expensive to install and maintain than roller paths with continuous individual rollers.